Quick: Rely on inferred types in GVN/LVN/DCE.

Fix LVN::GetEndingVregValueNumberImpl() to check whether
the requested wideness matches the SSA register type as
recorded in MIRGraph::reg_location_.

Add DCHECKs that the wideness matches when getting/setting
sreg values, update Phi handling in LVN/DCE to use the type
from MIRGraph::reg_location_ instead of determining it from
the sreg value maps which would now trigger the DCHECKs.
Update tests to initialize MIRGraph::reg_location_.

Reenable DCE.

Bug: 20572509
Change-Id: I1a4d4e32cd57807ca8b56d2f3ed5e1288660b82e

7 files changed, 198 insertions, 131 deletions

diff --git a/compiler/dex/global_value_numbering_test.cc b/compiler/dex/global_value_numbering_test.cc
index c538d0b..c8aa990 100644
--- a/compiler/dex/global_value_numbering_test.cc
+++ b/compiler/dex/global_value_numbering_test.cc
@@ -290,6 +290,15 @@ class GlobalValueNumberingTest : public testing::Test {
     DoPrepareVregToSsaMapExit(bb_id, map, count);
   }
 
+  template <size_t count>
+  void MarkAsWideSRegs(const int32_t (&sregs)[count]) {
+    for (int32_t sreg : sregs) {
+      cu_.mir_graph->reg_location_[sreg].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].high_word = true;
+    }
+  }
+
   void PerformGVN() {
     DoPerformGVN<LoopRepeatingTopologicalSortIterator>();
   }
@@ -360,9 +369,11 @@ class GlobalValueNumberingTest : public testing::Test {
     cu_.access_flags = kAccStatic;  // Don't let "this" interfere with this test.
     allocator_.reset(ScopedArenaAllocator::Create(&cu_.arena_stack));
     // By default, the zero-initialized reg_location_[.] with ref == false tells LVN that
-    // 0 constants are integral, not references. Nothing else is used by LVN/GVN.
+    // 0 constants are integral, not references, and the values are all narrow.
+    // Nothing else is used by LVN/GVN. Tests can override the default values as needed.
     cu_.mir_graph->reg_location_ =
         cu_.arena.AllocArray<RegLocation>(kMaxSsaRegs, kArenaAllocRegAlloc);
+    cu_.mir_graph->num_ssa_regs_ = kMaxSsaRegs;
     // Bind all possible sregs to live vregs for test purposes.
     live_in_v_->SetInitialBits(kMaxSsaRegs);
     cu_.mir_graph->ssa_base_vregs_.reserve(kMaxSsaRegs);
@@ -910,14 +921,14 @@ TEST_F(GlobalValueNumberingTestDiamond, AliasingArrays) {
       DEF_IGET(6, Instruction::AGET_OBJECT, 3u, 200u, 201u),  // Same as at the left side.
 
       DEF_AGET(3, Instruction::AGET_WIDE, 4u, 300u, 301u),
-      DEF_CONST(5, Instruction::CONST_WIDE, 5u, 1000),
-      DEF_APUT(5, Instruction::APUT_WIDE, 5u, 300u, 301u),
-      DEF_AGET(6, Instruction::AGET_WIDE, 7u, 300u, 301u),  // Differs from the top and the CONST.
+      DEF_CONST(5, Instruction::CONST_WIDE, 6u, 1000),
+      DEF_APUT(5, Instruction::APUT_WIDE, 6u, 300u, 301u),
+      DEF_AGET(6, Instruction::AGET_WIDE, 8u, 300u, 301u),  // Differs from the top and the CONST.
 
-      DEF_AGET(3, Instruction::AGET_SHORT, 8u, 400u, 401u),
-      DEF_CONST(3, Instruction::CONST, 9u, 2000),
-      DEF_APUT(4, Instruction::APUT_SHORT, 9u, 400u, 401u),
-      DEF_APUT(5, Instruction::APUT_SHORT, 9u, 400u, 401u),
+      DEF_AGET(3, Instruction::AGET_SHORT, 10u, 400u, 401u),
+      DEF_CONST(3, Instruction::CONST, 11u, 2000),
+      DEF_APUT(4, Instruction::APUT_SHORT, 11u, 400u, 401u),
+      DEF_APUT(5, Instruction::APUT_SHORT, 11u, 400u, 401u),
       DEF_AGET(6, Instruction::AGET_SHORT, 12u, 400u, 401u),  // Differs from the top, == CONST.
 
       DEF_AGET(3, Instruction::AGET_CHAR, 13u, 500u, 501u),
@@ -939,6 +950,8 @@ TEST_F(GlobalValueNumberingTestDiamond, AliasingArrays) {
   };
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 4, 6, 8 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN();
   ASSERT_EQ(arraysize(mirs), value_names_.size());
   EXPECT_EQ(value_names_[0], value_names_[1]);
@@ -1057,6 +1070,12 @@ TEST_F(GlobalValueNumberingTestDiamond, PhiWide) {
   };
 
   PrepareMIRs(mirs);
+  for (size_t i = 0u; i != arraysize(mirs); ++i) {
+    if ((mirs_[i].ssa_rep->defs[0] % 2) == 0) {
+      const int32_t wide_sregs[] = { mirs_[i].ssa_rep->defs[0] };
+      MarkAsWideSRegs(wide_sregs);
+    }
+  }
   PerformGVN();
   ASSERT_EQ(arraysize(mirs), value_names_.size());
   EXPECT_EQ(value_names_[0], value_names_[7]);
@@ -1493,27 +1512,27 @@ TEST_F(GlobalValueNumberingTestLoop, AliasingArrays) {
   static const MIRDef mirs[] = {
       // NOTE: MIRs here are ordered by unique tests. They will be put into appropriate blocks.
       DEF_AGET(3, Instruction::AGET_WIDE, 0u, 100u, 101u),
-      DEF_AGET(4, Instruction::AGET_WIDE, 1u, 100u, 101u),   // Same as at the top.
-      DEF_AGET(5, Instruction::AGET_WIDE, 2u, 100u, 101u),   // Same as at the top.
+      DEF_AGET(4, Instruction::AGET_WIDE, 2u, 100u, 101u),   // Same as at the top.
+      DEF_AGET(5, Instruction::AGET_WIDE, 4u, 100u, 101u),   // Same as at the top.
 
-      DEF_AGET(3, Instruction::AGET_BYTE, 3u, 200u, 201u),
-      DEF_AGET(4, Instruction::AGET_BYTE, 4u, 200u, 201u),  // Differs from top...
-      DEF_APUT(4, Instruction::APUT_BYTE, 5u, 200u, 201u),  // Because of this IPUT.
-      DEF_AGET(5, Instruction::AGET_BYTE, 6u, 200u, 201u),  // Differs from top and the loop AGET.
+      DEF_AGET(3, Instruction::AGET_BYTE, 6u, 200u, 201u),
+      DEF_AGET(4, Instruction::AGET_BYTE, 7u, 200u, 201u),  // Differs from top...
+      DEF_APUT(4, Instruction::APUT_BYTE, 8u, 200u, 201u),  // Because of this IPUT.
+      DEF_AGET(5, Instruction::AGET_BYTE, 9u, 200u, 201u),  // Differs from top and the loop AGET.
 
-      DEF_AGET(3, Instruction::AGET, 7u, 300u, 301u),
-      DEF_APUT(4, Instruction::APUT, 8u, 300u, 301u),   // Because of this IPUT...
-      DEF_AGET(4, Instruction::AGET, 9u, 300u, 301u),   // Differs from top.
-      DEF_AGET(5, Instruction::AGET, 10u, 300u, 301u),  // Differs from top but == the loop AGET.
+      DEF_AGET(3, Instruction::AGET, 10u, 300u, 301u),
+      DEF_APUT(4, Instruction::APUT, 11u, 300u, 301u),  // Because of this IPUT...
+      DEF_AGET(4, Instruction::AGET, 12u, 300u, 301u),   // Differs from top.
+      DEF_AGET(5, Instruction::AGET, 13u, 300u, 301u),  // Differs from top but == the loop AGET.
 
-      DEF_CONST(3, Instruction::CONST, 11u, 3000),
-      DEF_APUT(3, Instruction::APUT_CHAR, 11u, 400u, 401u),
-      DEF_APUT(3, Instruction::APUT_CHAR, 11u, 400u, 402u),
-      DEF_AGET(4, Instruction::AGET_CHAR, 14u, 400u, 401u),  // Differs from 11u and 16u.
-      DEF_AGET(4, Instruction::AGET_CHAR, 15u, 400u, 402u),  // Same as 14u.
-      DEF_CONST(4, Instruction::CONST, 16u, 4000),
-      DEF_APUT(4, Instruction::APUT_CHAR, 16u, 400u, 401u),
-      DEF_APUT(4, Instruction::APUT_CHAR, 16u, 400u, 402u),
+      DEF_CONST(3, Instruction::CONST, 14u, 3000),
+      DEF_APUT(3, Instruction::APUT_CHAR, 14u, 400u, 401u),
+      DEF_APUT(3, Instruction::APUT_CHAR, 14u, 400u, 402u),
+      DEF_AGET(4, Instruction::AGET_CHAR, 15u, 400u, 401u),  // Differs from 11u and 16u.
+      DEF_AGET(4, Instruction::AGET_CHAR, 16u, 400u, 402u),  // Same as 14u.
+      DEF_CONST(4, Instruction::CONST, 17u, 4000),
+      DEF_APUT(4, Instruction::APUT_CHAR, 17u, 400u, 401u),
+      DEF_APUT(4, Instruction::APUT_CHAR, 17u, 400u, 402u),
       DEF_AGET(5, Instruction::AGET_CHAR, 19u, 400u, 401u),  // Differs from 11u and 14u...
       DEF_AGET(5, Instruction::AGET_CHAR, 20u, 400u, 402u),  // and same as the CONST 16u.
 
@@ -1531,6 +1550,8 @@ TEST_F(GlobalValueNumberingTestLoop, AliasingArrays) {
   };
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 0, 2, 4 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN();
   ASSERT_EQ(arraysize(mirs), value_names_.size());
   EXPECT_EQ(value_names_[0], value_names_[1]);
diff --git a/compiler/dex/gvn_dead_code_elimination.cc b/compiler/dex/gvn_dead_code_elimination.cc
index bd7bd71..4f0e9d1 100644
--- a/compiler/dex/gvn_dead_code_elimination.cc
+++ b/compiler/dex/gvn_dead_code_elimination.cc
@@ -984,18 +984,17 @@ bool GvnDeadCodeElimination::RecordMIR(MIR* mir) {
   uint16_t opcode = mir->dalvikInsn.opcode;
   switch (opcode) {
     case kMirOpPhi: {
-      // We can't recognize wide variables in Phi from num_defs == 2 as we've got two Phis instead.
+      // Determine if this Phi is merging wide regs.
+      RegLocation raw_dest = gvn_->GetMirGraph()->GetRawDest(mir);
+      if (raw_dest.high_word) {
+        // This is the high part of a wide reg. Ignore the Phi.
+        return false;
+      }
+      bool wide = raw_dest.wide;
+      // Record the value.
       DCHECK_EQ(mir->ssa_rep->num_defs, 1);
       int s_reg = mir->ssa_rep->defs[0];
-      bool wide = false;
-      uint16_t new_value = lvn_->GetSregValue(s_reg);
-      if (new_value == kNoValue) {
-        wide = true;
-        new_value = lvn_->GetSregValueWide(s_reg);
-        if (new_value == kNoValue) {
-          return false;  // Ignore the high word Phi.
-        }
-      }
+      uint16_t new_value = wide ? lvn_->GetSregValueWide(s_reg) : lvn_->GetSregValue(s_reg);
 
       int v_reg = mir_graph_->SRegToVReg(s_reg);
       DCHECK_EQ(vreg_chains_.CurrentValue(v_reg), kNoValue);  // No previous def for v_reg.
diff --git a/compiler/dex/gvn_dead_code_elimination_test.cc b/compiler/dex/gvn_dead_code_elimination_test.cc
index 3eb372c..f9f0882 100644
--- a/compiler/dex/gvn_dead_code_elimination_test.cc
+++ b/compiler/dex/gvn_dead_code_elimination_test.cc
@@ -406,6 +406,15 @@ class GvnDeadCodeEliminationTest : public testing::Test {
     }
   }
 
+  template <size_t count>
+  void MarkAsWideSRegs(const int32_t (&sregs)[count]) {
+    for (int32_t sreg : sregs) {
+      cu_.mir_graph->reg_location_[sreg].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].high_word = true;
+    }
+  }
+
   void PerformDCE() {
     FillVregToSsaRegExitMaps();
     cu_.mir_graph->GetNumOfCodeAndTempVRs();
@@ -467,9 +476,11 @@ class GvnDeadCodeEliminationTest : public testing::Test {
     cu_.access_flags = kAccStatic;  // Don't let "this" interfere with this test.
     allocator_.reset(ScopedArenaAllocator::Create(&cu_.arena_stack));
     // By default, the zero-initialized reg_location_[.] with ref == false tells LVN that
-    // 0 constants are integral, not references. Nothing else is used by LVN/GVN.
+    // 0 constants are integral, not references, and the values are all narrow.
+    // Nothing else is used by LVN/GVN. Tests can override the default values as needed.
     cu_.mir_graph->reg_location_ = static_cast<RegLocation*>(cu_.arena.Alloc(
         kMaxSsaRegs * sizeof(cu_.mir_graph->reg_location_[0]), kArenaAllocRegAlloc));
+    cu_.mir_graph->num_ssa_regs_ = kMaxSsaRegs;
     // Bind all possible sregs to live vregs for test purposes.
     live_in_v_->SetInitialBits(kMaxSsaRegs);
     cu_.mir_graph->ssa_base_vregs_.reserve(kMaxSsaRegs);
@@ -705,6 +716,8 @@ TEST_F(GvnDeadCodeEliminationTestSimple, Rename4) {
   PrepareSRegToVRegMap(sreg_to_vreg_map);
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 3 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN_DCE();
 
   ASSERT_EQ(arraysize(mirs), value_names_.size());
@@ -745,6 +758,8 @@ TEST_F(GvnDeadCodeEliminationTestSimple, Rename5) {
 
   PrepareIFields(ifields);
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 5 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN_DCE();
 
   ASSERT_EQ(arraysize(mirs), value_names_.size());
@@ -777,6 +792,8 @@ TEST_F(GvnDeadCodeEliminationTestSimple, Rename6) {
   PrepareSRegToVRegMap(sreg_to_vreg_map);
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 0, 2 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN_DCE();
 
   ASSERT_EQ(arraysize(mirs), value_names_.size());
@@ -1255,6 +1272,8 @@ TEST_F(GvnDeadCodeEliminationTestSimple, Simple4) {
 
   PrepareIFields(ifields);
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 1, 6 };
+  MarkAsWideSRegs(wide_sregs);
   PerformGVN_DCE();
 
   ASSERT_EQ(arraysize(mirs), value_names_.size());
diff --git a/compiler/dex/local_value_numbering.cc b/compiler/dex/local_value_numbering.cc
index cdf5e38..cc9dbe4 100644
--- a/compiler/dex/local_value_numbering.cc
+++ b/compiler/dex/local_value_numbering.cc
@@ -1152,28 +1152,20 @@ uint16_t LocalValueNumbering::HandlePhi(MIR* mir) {
     // Running LVN without a full GVN?
     return kNoValue;
   }
-  int32_t* uses = mir->ssa_rep->uses;
-  // Try to find out if this is merging wide regs.
-  if (mir->ssa_rep->defs[0] != 0 &&
-      sreg_wide_value_map_.count(mir->ssa_rep->defs[0] - 1) != 0u) {
+  // Determine if this Phi is merging wide regs.
+  RegLocation raw_dest = gvn_->GetMirGraph()->GetRawDest(mir);
+  if (raw_dest.high_word) {
     // This is the high part of a wide reg. Ignore the Phi.
     return kNoValue;
   }
-  BasicBlockId* incoming = mir->meta.phi_incoming;
-  int16_t pos = 0;
-  // Check if we're merging a wide value based on the first merged LVN.
-  const LocalValueNumbering* first_lvn = gvn_->merge_lvns_[0];
-  DCHECK_LT(pos, mir->ssa_rep->num_uses);
-  while (incoming[pos] != first_lvn->Id()) {
-    ++pos;
-    DCHECK_LT(pos, mir->ssa_rep->num_uses);
-  }
-  int first_s_reg = uses[pos];
-  bool wide = (first_lvn->sreg_wide_value_map_.count(first_s_reg) != 0u);
+  bool wide = raw_dest.wide;
   // Iterate over *merge_lvns_ and skip incoming sregs for BBs without associated LVN.
   merge_names_.clear();
   uint16_t value_name = kNoValue;
   bool same_values = true;
+  BasicBlockId* incoming = mir->meta.phi_incoming;
+  int32_t* uses = mir->ssa_rep->uses;
+  int16_t pos = 0;
   for (const LocalValueNumbering* lvn : gvn_->merge_lvns_) {
     DCHECK_LT(pos, mir->ssa_rep->num_uses);
     while (incoming[pos] != lvn->Id()) {
@@ -1994,6 +1986,9 @@ uint16_t LocalValueNumbering::GetEndingVregValueNumberImpl(int v_reg, bool wide)
   if (s_reg == INVALID_SREG) {
     return kNoValue;
   }
+  if (gvn_->GetMirGraph()->GetRegLocation(s_reg).wide != wide) {
+    return kNoValue;
+  }
   if (wide) {
     int high_s_reg = bb->data_flow_info->vreg_to_ssa_map_exit[v_reg + 1];
     if (high_s_reg != s_reg + 1) {
diff --git a/compiler/dex/local_value_numbering.h b/compiler/dex/local_value_numbering.h
index 379c952..67fb647 100644
--- a/compiler/dex/local_value_numbering.h
+++ b/compiler/dex/local_value_numbering.h
@@ -53,10 +53,12 @@ class LocalValueNumbering : public DeletableArenaObject<kArenaAllocMisc> {
   }
 
   uint16_t GetSregValue(uint16_t s_reg) const {
+    DCHECK(!gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
     return GetSregValueImpl(s_reg, &sreg_value_map_);
   }
 
   uint16_t GetSregValueWide(uint16_t s_reg) const {
+    DCHECK(gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
     return GetSregValueImpl(s_reg, &sreg_wide_value_map_);
   }
 
@@ -123,21 +125,27 @@ class LocalValueNumbering : public DeletableArenaObject<kArenaAllocMisc> {
 
   void SetOperandValue(uint16_t s_reg, uint16_t value) {
     DCHECK_EQ(sreg_wide_value_map_.count(s_reg), 0u);
+    DCHECK(!gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
     SetOperandValueImpl(s_reg, value, &sreg_value_map_);
   }
 
   uint16_t GetOperandValue(int s_reg) const {
     DCHECK_EQ(sreg_wide_value_map_.count(s_reg), 0u);
+    DCHECK(!gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
     return GetOperandValueImpl(s_reg, &sreg_value_map_);
   }
 
   void SetOperandValueWide(uint16_t s_reg, uint16_t value) {
     DCHECK_EQ(sreg_value_map_.count(s_reg), 0u);
+    DCHECK(gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
+    DCHECK(!gvn_->GetMirGraph()->GetRegLocation(s_reg).high_word);
     SetOperandValueImpl(s_reg, value, &sreg_wide_value_map_);
   }
 
   uint16_t GetOperandValueWide(int s_reg) const {
     DCHECK_EQ(sreg_value_map_.count(s_reg), 0u);
+    DCHECK(gvn_->GetMirGraph()->GetRegLocation(s_reg).wide);
+    DCHECK(!gvn_->GetMirGraph()->GetRegLocation(s_reg).high_word);
     return GetOperandValueImpl(s_reg, &sreg_wide_value_map_);
   }
 
@@ -331,7 +339,7 @@ class LocalValueNumbering : public DeletableArenaObject<kArenaAllocMisc> {
 
   void CopyLiveSregValues(SregValueMap* dest, const SregValueMap& src);
 
-  // Intersect maps as sets. The value type must be equality-comparable.
+  // Intersect SSA reg value maps as sets, ignore dead regs.
   template <SregValueMap LocalValueNumbering::* map_ptr>
   void IntersectSregValueMaps();
 
diff --git a/compiler/dex/local_value_numbering_test.cc b/compiler/dex/local_value_numbering_test.cc
index 0393410..bd00690 100644
--- a/compiler/dex/local_value_numbering_test.cc
+++ b/compiler/dex/local_value_numbering_test.cc
@@ -182,6 +182,15 @@ class LocalValueNumberingTest : public testing::Test {
         ~MirSFieldLoweringInfo::kFlagClassIsInitialized;
   }
 
+  template <size_t count>
+  void MarkAsWideSRegs(const int32_t (&sregs)[count]) {
+    for (int32_t sreg : sregs) {
+      cu_.mir_graph->reg_location_[sreg].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].wide = true;
+      cu_.mir_graph->reg_location_[sreg + 1].high_word = true;
+    }
+  }
+
   void PerformLVN() {
     cu_.mir_graph->temp_.gvn.ifield_ids =  GlobalValueNumbering::PrepareGvnFieldIds(
         allocator_.get(), cu_.mir_graph->ifield_lowering_infos_);
@@ -210,9 +219,11 @@ class LocalValueNumberingTest : public testing::Test {
     cu_.mir_graph.reset(new MIRGraph(&cu_, &cu_.arena));
     allocator_.reset(ScopedArenaAllocator::Create(&cu_.arena_stack));
     // By default, the zero-initialized reg_location_[.] with ref == false tells LVN that
-    // 0 constants are integral, not references. Nothing else is used by LVN/GVN.
+    // 0 constants are integral, not references, and the values are all narrow.
+    // Nothing else is used by LVN/GVN. Tests can override the default values as needed.
     cu_.mir_graph->reg_location_ = static_cast<RegLocation*>(cu_.arena.Alloc(
         kMaxSsaRegs * sizeof(cu_.mir_graph->reg_location_[0]), kArenaAllocRegAlloc));
+    cu_.mir_graph->num_ssa_regs_ = kMaxSsaRegs;
   }
 
   static constexpr size_t kMaxSsaRegs = 16384u;
@@ -379,26 +390,28 @@ TEST_F(LocalValueNumberingTest, UnresolvedIField) {
       { 3u, 0u, 0u, false, kDexMemAccessWord },  // Unresolved field.
   };
   static const MIRDef mirs[] = {
-      DEF_UNIQUE_REF(Instruction::NEW_INSTANCE, 20u),
-      DEF_IGET(Instruction::IGET, 1u, 20u, 0u),             // Resolved field #1, unique object.
-      DEF_IGET(Instruction::IGET, 2u, 21u, 0u),             // Resolved field #1.
-      DEF_IGET_WIDE(Instruction::IGET_WIDE, 3u, 21u, 1u),   // Resolved field #2.
-      DEF_IGET(Instruction::IGET, 4u, 22u, 2u),             // Unresolved IGET can be "acquire".
-      DEF_IGET(Instruction::IGET, 5u, 20u, 0u),             // Resolved field #1, unique object.
-      DEF_IGET(Instruction::IGET, 6u, 21u, 0u),             // Resolved field #1.
-      DEF_IGET_WIDE(Instruction::IGET_WIDE, 7u, 21u, 1u),   // Resolved field #2.
-      DEF_IPUT(Instruction::IPUT, 8u, 22u, 2u),             // IPUT clobbers field #1 (#2 is wide).
-      DEF_IGET(Instruction::IGET, 9u, 20u, 0u),             // Resolved field #1, unique object.
-      DEF_IGET(Instruction::IGET, 10u, 21u, 0u),            // Resolved field #1, new value name.
-      DEF_IGET_WIDE(Instruction::IGET_WIDE, 11u, 21u, 1u),  // Resolved field #2.
-      DEF_IGET_WIDE(Instruction::IGET_WIDE, 12u, 20u, 1u),  // Resolved field #2, unique object.
-      DEF_IPUT(Instruction::IPUT, 13u, 20u, 2u),            // IPUT clobbers field #1 (#2 is wide).
-      DEF_IGET(Instruction::IGET, 14u, 20u, 0u),            // Resolved field #1, unique object.
-      DEF_IGET_WIDE(Instruction::IGET_WIDE, 15u, 20u, 1u),  // Resolved field #2, unique object.
+      DEF_UNIQUE_REF(Instruction::NEW_INSTANCE, 30u),
+      DEF_IGET(Instruction::IGET, 1u, 30u, 0u),             // Resolved field #1, unique object.
+      DEF_IGET(Instruction::IGET, 2u, 31u, 0u),             // Resolved field #1.
+      DEF_IGET_WIDE(Instruction::IGET_WIDE, 3u, 31u, 1u),   // Resolved field #2.
+      DEF_IGET(Instruction::IGET, 5u, 32u, 2u),             // Unresolved IGET can be "acquire".
+      DEF_IGET(Instruction::IGET, 6u, 30u, 0u),             // Resolved field #1, unique object.
+      DEF_IGET(Instruction::IGET, 7u, 31u, 0u),             // Resolved field #1.
+      DEF_IGET_WIDE(Instruction::IGET_WIDE, 8u, 31u, 1u),   // Resolved field #2.
+      DEF_IPUT(Instruction::IPUT, 10u, 32u, 2u),            // IPUT clobbers field #1 (#2 is wide).
+      DEF_IGET(Instruction::IGET, 11u, 30u, 0u),            // Resolved field #1, unique object.
+      DEF_IGET(Instruction::IGET, 12u, 31u, 0u),            // Resolved field #1, new value name.
+      DEF_IGET_WIDE(Instruction::IGET_WIDE, 13u, 31u, 1u),  // Resolved field #2.
+      DEF_IGET_WIDE(Instruction::IGET_WIDE, 15u, 30u, 1u),  // Resolved field #2, unique object.
+      DEF_IPUT(Instruction::IPUT, 17u, 30u, 2u),            // IPUT clobbers field #1 (#2 is wide).
+      DEF_IGET(Instruction::IGET, 18u, 30u, 0u),            // Resolved field #1, unique object.
+      DEF_IGET_WIDE(Instruction::IGET_WIDE, 19u, 30u, 1u),  // Resolved field #2, unique object.
   };
 
   PrepareIFields(ifields);
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 3, 8, 13, 15, 19 };
+  MarkAsWideSRegs(wide_sregs);
   PerformLVN();
   ASSERT_EQ(value_names_.size(), 16u);
   // Unresolved field is potentially volatile, so we need to adhere to the volatile semantics.
@@ -430,16 +443,18 @@ TEST_F(LocalValueNumberingTest, UnresolvedSField) {
   static const MIRDef mirs[] = {
       DEF_SGET(Instruction::SGET, 0u, 0u),            // Resolved field #1.
       DEF_SGET_WIDE(Instruction::SGET_WIDE, 1u, 1u),  // Resolved field #2.
-      DEF_SGET(Instruction::SGET, 2u, 2u),            // Unresolved SGET can be "acquire".
-      DEF_SGET(Instruction::SGET, 3u, 0u),            // Resolved field #1.
-      DEF_SGET_WIDE(Instruction::SGET_WIDE, 4u, 1u),  // Resolved field #2.
-      DEF_SPUT(Instruction::SPUT, 5u, 2u),            // SPUT clobbers field #1 (#2 is wide).
-      DEF_SGET(Instruction::SGET, 6u, 0u),            // Resolved field #1.
-      DEF_SGET_WIDE(Instruction::SGET_WIDE, 7u, 1u),  // Resolved field #2.
+      DEF_SGET(Instruction::SGET, 3u, 2u),            // Unresolved SGET can be "acquire".
+      DEF_SGET(Instruction::SGET, 4u, 0u),            // Resolved field #1.
+      DEF_SGET_WIDE(Instruction::SGET_WIDE, 5u, 1u),  // Resolved field #2.
+      DEF_SPUT(Instruction::SPUT, 7u, 2u),            // SPUT clobbers field #1 (#2 is wide).
+      DEF_SGET(Instruction::SGET, 8u, 0u),            // Resolved field #1.
+      DEF_SGET_WIDE(Instruction::SGET_WIDE, 9u, 1u),  // Resolved field #2.
   };
 
   PrepareSFields(sfields);
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 1, 5, 9 };
+  MarkAsWideSRegs(wide_sregs);
   PerformLVN();
   ASSERT_EQ(value_names_.size(), 8u);
   // Unresolved field is potentially volatile, so we need to adhere to the volatile semantics.
@@ -585,18 +600,20 @@ TEST_F(LocalValueNumberingTest, EscapingRefs) {
       DEF_IGET(Instruction::IGET, 7u, 20u, 0u),              // New value.
       DEF_IGET(Instruction::IGET, 8u, 20u, 1u),              // Still the same.
       DEF_IPUT_WIDE(Instruction::IPUT_WIDE, 9u, 31u, 3u),    // No aliasing, different type.
-      DEF_IGET(Instruction::IGET, 10u, 20u, 0u),
-      DEF_IGET(Instruction::IGET, 11u, 20u, 1u),
-      DEF_IPUT_WIDE(Instruction::IPUT_WIDE, 12u, 31u, 5u),   // No aliasing, different type.
-      DEF_IGET(Instruction::IGET, 13u, 20u, 0u),
-      DEF_IGET(Instruction::IGET, 14u, 20u, 1u),
-      DEF_IPUT(Instruction::IPUT, 15u, 31u, 4u),             // Aliasing, same type.
-      DEF_IGET(Instruction::IGET, 16u, 20u, 0u),
-      DEF_IGET(Instruction::IGET, 17u, 20u, 1u),
+      DEF_IGET(Instruction::IGET, 11u, 20u, 0u),
+      DEF_IGET(Instruction::IGET, 12u, 20u, 1u),
+      DEF_IPUT_WIDE(Instruction::IPUT_WIDE, 13u, 31u, 5u),   // No aliasing, different type.
+      DEF_IGET(Instruction::IGET, 15u, 20u, 0u),
+      DEF_IGET(Instruction::IGET, 16u, 20u, 1u),
+      DEF_IPUT(Instruction::IPUT, 17u, 31u, 4u),             // Aliasing, same type.
+      DEF_IGET(Instruction::IGET, 18u, 20u, 0u),
+      DEF_IGET(Instruction::IGET, 19u, 20u, 1u),
   };
 
   PrepareIFields(ifields);
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 9, 13 };
+  MarkAsWideSRegs(wide_sregs);
   PerformLVN();
   ASSERT_EQ(value_names_.size(), 18u);
   EXPECT_EQ(value_names_[1], value_names_[4]);
@@ -626,14 +643,16 @@ TEST_F(LocalValueNumberingTest, EscapingArrayRefs) {
       DEF_AGET(Instruction::AGET, 4u, 20u, 40u),
       DEF_AGET(Instruction::AGET, 5u, 20u, 41u),
       DEF_APUT_WIDE(Instruction::APUT_WIDE, 6u, 31u, 43u),  // No aliasing, different type.
-      DEF_AGET(Instruction::AGET, 7u, 20u, 40u),
-      DEF_AGET(Instruction::AGET, 8u, 20u, 41u),
-      DEF_APUT(Instruction::APUT, 9u, 32u, 40u),            // May alias with all elements.
-      DEF_AGET(Instruction::AGET, 10u, 20u, 40u),           // New value (same index name).
-      DEF_AGET(Instruction::AGET, 11u, 20u, 41u),           // New value (different index name).
+      DEF_AGET(Instruction::AGET, 8u, 20u, 40u),
+      DEF_AGET(Instruction::AGET, 9u, 20u, 41u),
+      DEF_APUT(Instruction::APUT, 10u, 32u, 40u),           // May alias with all elements.
+      DEF_AGET(Instruction::AGET, 11u, 20u, 40u),           // New value (same index name).
+      DEF_AGET(Instruction::AGET, 12u, 20u, 41u),           // New value (different index name).
   };
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 6 };
+  MarkAsWideSRegs(wide_sregs);
   PerformLVN();
   ASSERT_EQ(value_names_.size(), 12u);
   EXPECT_EQ(value_names_[1], value_names_[4]);
@@ -769,6 +788,8 @@ TEST_F(LocalValueNumberingTest, DivZeroCheck) {
   };
 
   PrepareMIRs(mirs);
+  static const int32_t wide_sregs[] = { 5, 7, 12, 14, 16 };
+  MarkAsWideSRegs(wide_sregs);
   PerformLVN();
   for (size_t i = 0u; i != mir_count_; ++i) {
     int expected = expected_ignore_div_zero_check[i] ? MIR_IGNORE_DIV_ZERO_CHECK : 0u;
@@ -780,51 +801,55 @@ TEST_F(LocalValueNumberingTest, ConstWide) {
   static const MIRDef mirs[] = {
       // Core reg constants.
       DEF_CONST(Instruction::CONST_WIDE_16, 0u, 0),
-      DEF_CONST(Instruction::CONST_WIDE_16, 1u, 1),
-      DEF_CONST(Instruction::CONST_WIDE_16, 2u, -1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 3u, 1 << 16),
-      DEF_CONST(Instruction::CONST_WIDE_32, 4u, -1 << 16),
-      DEF_CONST(Instruction::CONST_WIDE_32, 5u, (1 << 16) + 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 6u, (1 << 16) - 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 7u, -(1 << 16) + 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 8u, -(1 << 16) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 9u, INT64_C(1) << 32),
-      DEF_CONST(Instruction::CONST_WIDE, 10u, INT64_C(-1) << 32),
-      DEF_CONST(Instruction::CONST_WIDE, 11u, (INT64_C(1) << 32) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 12u, (INT64_C(1) << 32) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 13u, (INT64_C(-1) << 32) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 14u, (INT64_C(-1) << 32) - 1),
-      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 15u, 1),       // Effectively 1 << 48.
-      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 16u, 0xffff),  // Effectively -1 << 48.
-      DEF_CONST(Instruction::CONST_WIDE, 17u, (INT64_C(1) << 48) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 18u, (INT64_C(1) << 48) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 19u, (INT64_C(-1) << 48) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 20u, (INT64_C(-1) << 48) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_16, 2u, 1),
+      DEF_CONST(Instruction::CONST_WIDE_16, 4u, -1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 6u, 1 << 16),
+      DEF_CONST(Instruction::CONST_WIDE_32, 8u, -1 << 16),
+      DEF_CONST(Instruction::CONST_WIDE_32, 10u, (1 << 16) + 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 12u, (1 << 16) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 14u, -(1 << 16) + 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 16u, -(1 << 16) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 18u, INT64_C(1) << 32),
+      DEF_CONST(Instruction::CONST_WIDE, 20u, INT64_C(-1) << 32),
+      DEF_CONST(Instruction::CONST_WIDE, 22u, (INT64_C(1) << 32) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 24u, (INT64_C(1) << 32) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 26u, (INT64_C(-1) << 32) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 28u, (INT64_C(-1) << 32) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 30u, 1),       // Effectively 1 << 48.
+      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 32u, 0xffff),  // Effectively -1 << 48.
+      DEF_CONST(Instruction::CONST_WIDE, 34u, (INT64_C(1) << 48) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 36u, (INT64_C(1) << 48) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 38u, (INT64_C(-1) << 48) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 40u, (INT64_C(-1) << 48) - 1),
       // FP reg constants.
-      DEF_CONST(Instruction::CONST_WIDE_16, 21u, 0),
-      DEF_CONST(Instruction::CONST_WIDE_16, 22u, 1),
-      DEF_CONST(Instruction::CONST_WIDE_16, 23u, -1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 24u, 1 << 16),
-      DEF_CONST(Instruction::CONST_WIDE_32, 25u, -1 << 16),
-      DEF_CONST(Instruction::CONST_WIDE_32, 26u, (1 << 16) + 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 27u, (1 << 16) - 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 28u, -(1 << 16) + 1),
-      DEF_CONST(Instruction::CONST_WIDE_32, 29u, -(1 << 16) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 30u, INT64_C(1) << 32),
-      DEF_CONST(Instruction::CONST_WIDE, 31u, INT64_C(-1) << 32),
-      DEF_CONST(Instruction::CONST_WIDE, 32u, (INT64_C(1) << 32) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 33u, (INT64_C(1) << 32) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 34u, (INT64_C(-1) << 32) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 35u, (INT64_C(-1) << 32) - 1),
-      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 36u, 1),       // Effectively 1 << 48.
-      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 37u, 0xffff),  // Effectively -1 << 48.
-      DEF_CONST(Instruction::CONST_WIDE, 38u, (INT64_C(1) << 48) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 39u, (INT64_C(1) << 48) - 1),
-      DEF_CONST(Instruction::CONST_WIDE, 40u, (INT64_C(-1) << 48) + 1),
-      DEF_CONST(Instruction::CONST_WIDE, 41u, (INT64_C(-1) << 48) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_16, 42u, 0),
+      DEF_CONST(Instruction::CONST_WIDE_16, 44u, 1),
+      DEF_CONST(Instruction::CONST_WIDE_16, 46u, -1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 48u, 1 << 16),
+      DEF_CONST(Instruction::CONST_WIDE_32, 50u, -1 << 16),
+      DEF_CONST(Instruction::CONST_WIDE_32, 52u, (1 << 16) + 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 54u, (1 << 16) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 56u, -(1 << 16) + 1),
+      DEF_CONST(Instruction::CONST_WIDE_32, 58u, -(1 << 16) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 60u, INT64_C(1) << 32),
+      DEF_CONST(Instruction::CONST_WIDE, 62u, INT64_C(-1) << 32),
+      DEF_CONST(Instruction::CONST_WIDE, 64u, (INT64_C(1) << 32) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 66u, (INT64_C(1) << 32) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 68u, (INT64_C(-1) << 32) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 70u, (INT64_C(-1) << 32) - 1),
+      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 72u, 1),       // Effectively 1 << 48.
+      DEF_CONST(Instruction::CONST_WIDE_HIGH16, 74u, 0xffff),  // Effectively -1 << 48.
+      DEF_CONST(Instruction::CONST_WIDE, 76u, (INT64_C(1) << 48) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 78u, (INT64_C(1) << 48) - 1),
+      DEF_CONST(Instruction::CONST_WIDE, 80u, (INT64_C(-1) << 48) + 1),
+      DEF_CONST(Instruction::CONST_WIDE, 82u, (INT64_C(-1) << 48) - 1),
   };
 
   PrepareMIRs(mirs);
+  for (size_t i = 0; i != arraysize(mirs); ++i) {
+    const int32_t wide_sregs[] = { mirs_[i].ssa_rep->defs[0] };
+    MarkAsWideSRegs(wide_sregs);
+  }
   for (size_t i = arraysize(mirs) / 2u; i != arraysize(mirs); ++i) {
     cu_.mir_graph->reg_location_[mirs_[i].ssa_rep->defs[0]].fp = true;
   }
diff --git a/compiler/dex/quick/quick_compiler.cc b/compiler/dex/quick/quick_compiler.cc
index 39eb117..73cfe92 100644
--- a/compiler/dex/quick/quick_compiler.cc
+++ b/compiler/dex/quick/quick_compiler.cc
@@ -575,7 +575,7 @@ static uint32_t kCompilerOptimizerDisableFlags = 0 |  // Disable specific optimi
   // (1 << kNullCheckElimination) |
   // (1 << kClassInitCheckElimination) |
   // (1 << kGlobalValueNumbering) |
-  (1 << kGvnDeadCodeElimination) |
+  // (1 << kGvnDeadCodeElimination) |
   // (1 << kLocalValueNumbering) |
   // (1 << kPromoteRegs) |
   // (1 << kTrackLiveTemps) |